Frank shows depressed side (9)
I believe the answer is:
downright
'frank' is the definition.
(I've seen this before)
'depressed side' is the wordplay.
'depressed' becomes 'down' (synonyms).
'side' becomes 'right'.
'down'+'right'='DOWNRIGHT'
'shows' is the link.
(Other definitions for downright that I've seen before include "Out-and-out" , "Absolutely!" , "Completely" , "Blatant" , "Utter, complete" .)